1. Field of the Invention;
The present invention relates to semi-bulk bags. More particularly, the present invention relates to a semi-bulk bag having an exterior fabric layer and an interior polyethlene liner glued therein for assuring maintenance of the liner while the contents of the bag are dumped, and also provides for a process to assure the liner in proper position within the bag.
2. General Background:
In the art of transporting of dry, free-flowing bulk materials such as sugar, flour, resins, etc., or even certain waste products, the use of bulk bags are well known to the industry, the bags consisting primarily of an upper receiving portion for receiving contents within the bag. The bag is then transported and a lower discharge outlet which would be sealed during transport is opened into a receiving bin, and the contents would be poured therefrom through the discharge outlet. In addition, material fabric bulk bags may be required to have an inner polyethylene liner for complete moisture, or contamination control, or federal requirements are such that the contents such as food products must be sealed within the polyethylene liner for purpose of purity as opposed to a plain fabric bag.
Although this type of system is common in the industry, there are several shortcomings in the present state of the art which need addressing. In particular, in the system whereby the polyethylene liner is insertable into the exterior fabric bag, the liner, of course, often times is simply a cylindrical continuous wall liner, which is inserted into the bag and tied off at the bottom end, with the contents poured into the top neck of the liner. As the inner liner fills out with contents, it theoretically fills out into the exterior fabric bag for transport. However, what often occurs is that as the liner is receiving the product, folds or creases in the liner prevent it from conforming to the shape of the exterior bag, and therefore the result is a void between the liner and the fabric bag, which is not filled, and therefore less contents are carried in the bag as would normally be available.
Perhaps a more significant problem is the problem encountered upon the bag releasing its contents through the lower discharge outlet as was described earlier. As the contents pour from the fabric bag and the liner, because the fact that the liner is not secured within the bag, the result is often that the liner itself will be pulled from the bag through the force of the pouring contents, and as often occurs, the liner itself would drop into the container, whether it be a bin or another type of receiving container. This, of course, is particularly undesirable in view of the fact the contents, which often times may be food substances, have in effect, become contaminanted by the liner being allowed to reside in the bin following pouring of the contents therefrom.
There are several patents which have been discovered as a result of a search of the art on the subject of liners and method of securing liners within an exterior of the frames, the most pertinent being as follows:
U.S. Pat. No. 4,505,694 issued to Okushita, entitled "Apparatus For Fabricating A Bag And Box Package", relates to a bag made of substantially rectangular super-imposed layers of flexible material hermetically sealed and upon inflation of the bag, the bag comes into close contact with the box ready to receive the desired product through a filament attached thereto.
U.S. Pat. No. 4,516,906 issued to Krein, entitled "Free Standing Waterproof Lining For Truck Industry", relates to a method of installing a continuous moisture proof film liner within a conventional cargo trailer by blowing a gentle stream of air into the bag as sufficient tension is applied to the upper edge and surface to direct the air into the rear of the trailer. It would simply be adhered to place via contact with the sides and the top of the container.
U.S. Pat. No. 3,576,154 issued to Breckmuller, entitled "Process And Apparatus For Manufacturing Bags Comprising a Liner Bag Which Protrudes From The Opening", involves a process which is related to the bag construction as to the inclusion of a liner bag within an exterior bag.
U.S. Pat. No. 3,630,798 issued to Wicks, entitled "Method Of Making Plastic-Lined Burlap Bag", teaches a method of forming a line bag extruding a strip of thermal plastic adhesive along an edge of a piece of bag allowing it to dry and forming a bag with the external stitch side and bottom seams with the adhesive strips along the outer edge of the open top.
U.S. Pat. No. 3,929,275 issued to Bolling, et al, entitled "Bags With Film Liners And Method Of Making, relates to a method of making a bag whereby flat non-gusseted plastic film tubing heat sealed transversely the tube length and can be combined with the Weber paper and a conventional bag machine to form a bag with a film liner.
U.S. Pat. No. 4,340,379 issued to Williamson, entitled "Reinforced Container For Bulk Material", relates to a container in the manufacture thereof for a reinforced receptacle for containing bulk material having a coextruded plastic multiplied tube having at least an inner and outer ply and having an upper and lower end with the reinforced sheet wrapped around the multiplied tube and encompassing the tube from the lower end to a hide-away so that the receptacle is filled with the bulk material.